In many industries, as, for example, in the mattress or bedding industry, it is common practice to secure a wire or rod, such as a spring element of a mattress, to a border wire with a clip made from sheet metal. Such clips are generally in a U-shape having an arcuate crown portion and oppositely spaced leg portions depending from the crown portion. The two wires to be connected are placed between the leg portions of the clip and the leg portions pushed together by a clinching tool, thus securing or locking the two wires together.
Such a clinching tool typically includes a J-shaped jaw into which the leading clip of a stack of clips is indexed. The clinching tool has a blade which shears off the first clip from a stack of clips placed inside the clinching tool. U.S. Pat. No. 2,574,811 shows such a clinching tool.
In order to operate the clinching tool, it is necessary to place a plurality of clips inside the clinching tool in an orderly fashion. The clips must be similarly oriented and in an abutting relationship to one another, each clip abutting the two adjacent clips in an orderly fashion. Clips must be interconnected to each other in a flexible manner so that the stack of clips can be wound into the clinching tool. The clips must also be interconnected with sufficient strength so that they are able to withstand high tensile forces associated with winding and unwinding of the stack of clips upon a spool in the clinching machine. Accidental breakage of the connector connecting adjacent clips would be detrimental to the operation of the clinching machine.
One common way used to interconnect similar U-shaped sheet metal clips together is by means of non-metal, elongated flexible members made of plastic. Slots or grooves through the arcuate portion of each U-shaped clip are lined up, such that the non-metallic flexible members may be placed inside all of the grooves in order to connect the clips together in a flexible manner.
U.S. Pat. No. 5,833,064 discloses a clip made of sheet metal having a U-shaped hook portion inside which is secured a sheet of cushioning material, such as plastic. When a wire is placed inside the hook portion, the cushioning material prevents wire-on-wire noise, such as squeaking. Over time, these plastic liners may wear out and allow an end portion of a sinuous wire to move/shift inside the worn plastic liner thereby creating unwanted squeaking or “noise”. The clip assemblies of U.S. Pat. No. 5,833,064 may be connected to identical clip assemblies in a string. The clips have prongs or tacks inherently formed from the sheet metal, the prongs being bent downwardly and adapted to be inserted into wooden rails of furniture frames.
Thus, there is a need for a U-shaped clip assembly which may be made partially of metal and partially of plastic which inhibits movement of the wire thereby preventing squeaking or “noise” after a sinuous spring is applied.
There is further a need for a metal clip for a U-shaped clip assembly which provides improved holding strength when inserted inside wooden rails of furniture frames.